The convoy flotillas knew that their only chance of action was with a submarine submerged, a form of warfare in which the result was so very frequently unknown and therefore unsatisfactory.
Under the new conditions the Admiralty took upon itself responsibility for the control of the ships of the Mercantile Marine in addition to its control of the movements of the Fleet.

Indeed the control of convoys was even more directly under the Admiralty than was the control of the Fleet.

In the latter case the proper system is for the Admiralty to indicate to the Commander-in-Chief, Grand Fleet, or to other Commands the objective, and to supply all the information possible regarding the strength of the enemy, his intentions and movements and such other information as can be of use to the Commander-in-Chief, but to leave the handling of the force to the Commander-in-Chief concerned.

This is the course which was usually followed during the late war.

It was my invariable practice when at the Admiralty.
In the case of convoys, however, a different system was necessary owing to the difficulty of transmitting information, the great delay that would be caused were this attempted, and the impossibility of control being exercised over all convoys at sea except by the Admiralty.
Consequently the actual movements of convoys for the greater part of their passage were directed by the Naval Staff.